Translation of the abstract (English)

In this work new ionic liquids based on the low symmetric difluoromono[1,2-oxalato(2-)-O,O�]borate -anion with several organic cations (tetraethylammonium-, 1-ethyl-3-methylimdazolium-, 1-butyl-3-methylimdazolium were used as cations) were prepared, especially for low temperature applications in electrochemical double layer capacitors.
One of the main aims was the decrease of the melting point ...

Translation of the abstract (English)

In this work new ionic liquids based on the low symmetric difluoromono[1,2-oxalato(2-)-O,O�]borate -anion with several organic cations (tetraethylammonium-, 1-ethyl-3-methylimdazolium-, 1-butyl-3-methylimdazolium were used as cations) were prepared, especially for low temperature applications in electrochemical double layer capacitors. One of the main aims was the decrease of the melting point by a decrease of the structure symmetry of the in double layer capacitors actually used standard electrolyte, tetraethylammoniumtetrafluoroborate. This should lead to an increase of the solubility and the conductivity of the new electrolytes compared to tetraethylammoniumtetrafluoroborate, especially at low temperatures. It could be shown that the melting point of tetraethylammoniumtetrafluoroborate could be decreased approximately of 350 °C from 362 °C to 33 °C for tetraethylammonium-difluoromono[1,2-oxalato(2-)-O,O�]borate by the substitution of two fluoro atoms by an oxalate groupe.The melting point could be further reduced to 18 °C by combination of the low symmetric difluorooxalatoborate with the low symmetric 1-ethyl-3-methylimdazolium-cation.Additionally, some trifluoroacetates with several organic cations with reduces symmetry (methyltriethylammonium-, N,N-ethyl-methylpyrrolidinium- were used as cations) and tetrakis(trifluoracetato)borates with the same cations have been studied.All electrolytes were characterized by conductivity measurements at several concentrations and temperatures as well as cyclic voltammetry experiments to check their conductivity, voltage stability and corrodibility at aluminium. Furthermore, the thermal stability and viscosity of the difluoromono[1,2-oxalato(2-)-O,O�]borates were investigated by differential scanning calorimetry- and viscosity measurements.